sparc/fp/_Q_dtoq.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 1994-1997, by Sun Microsystems, Inc.
 * All rights reserved.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "quad.h"

#ifdef __sparcv9

/*
 * _Qp_dtoq(pz, x) sets *pz = (long double)x.
 */
void
_Qp_dtoq(union longdouble *pz, double x)

#else

/*
 * _Q_dtoq(x) returns (long double)x.
 */
union longdouble
_Q_dtoq(double x)

#endif /* __sparcv9 */

{
#ifndef __sparcv9
    union longdouble    z;
#endif
    union xdouble       u;
    unsigned int        m, lhi, llo, fsr;

    /* extract the exponent */
    u.d = x;
    m = ((u.l.hi & 0x7ff00000) >> 4) + 0x3c000000;
    if (m == 0x3c000000) {
        /* x is zero or denormal */
        if ((u.l.hi & 0xfffff) | u.l.lo) {
            /* x is denormal, normalize it */
            m = 0x3c010000;
            lhi = u.l.hi & 0xfffff;
            llo = u.l.lo;
            do {
                lhi = (lhi << 1) | (llo >> 31);
                llo <<= 1;
                m -= 0x10000;
            } while ((lhi & 0x7ff00000) == 0);
            u.l.hi = (u.l.hi & 0x80000000) | lhi;
            u.l.lo = llo;
        } else {
            m = 0;
        }
    } else if (m == 0x43ff0000) {
        /* x is inf or nan */
        m = 0x7fff0000;
        if (((u.l.hi & 0x7ffff) | u.l.lo) && (u.l.hi & 0x80000) == 0) {
            /* snan, signal invalid */
            __quad_getfsrp(&fsr);
            if (fsr & FSR_NVM) {
                __quad_fdtoq(&x, &Z);
                QUAD_RETURN(Z);
            } else {
                fsr = (fsr & ~FSR_CEXC) | FSR_NVA | FSR_NVC;
                __quad_setfsrp(&fsr);
            }
            u.l.hi |= 0x80000;
        }
    }
    Z.l.msw = m | (u.l.hi & 0x80000000) | ((u.l.hi & 0xffff0) >> 4);
    Z.l.frac2 = (u.l.hi << 28) | (u.l.lo >> 4);
    Z.l.frac3 = u.l.lo << 28;
    Z.l.frac4 = 0;
    QUAD_RETURN(Z);
}